Initial checkin of gRPC to third_party/

third_party/grpc/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs

Index: third_party/grpc/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs
diff --git a/third_party/grpc/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs b/third_party/grpc/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs
new file mode 100644
index 0000000000000000000000000000000000000000..e810ffcdd03d565aedc853bda0757a8397cf9ff0
--- /dev/null
+++ b/third_party/grpc/src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs
@@ -0,0 +1,109 @@
+#region Copyright notice and license
+// Copyright 2015-2016, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#endregion
+using System;
+using System.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+
+using Grpc.Core.Logging;
+using Grpc.Core.Utils;
+
+namespace Grpc.Core.Internal
+{
+    internal delegate void NativeMetadataInterceptor(IntPtr statePtr, IntPtr serviceUrlPtr, IntPtr methodNamePtr, IntPtr callbackPtr, IntPtr userDataPtr, bool isDestroy);
+
+    internal class NativeMetadataCredentialsPlugin
+    {
+        const string GetMetadataExceptionMsg = "Exception occured in metadata credentials plugin.";
+        static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<NativeMetadataCredentialsPlugin>();
+        static readonly NativeMethods Native = NativeMethods.Get();
+
+        AsyncAuthInterceptor interceptor;
+        GCHandle gcHandle;
+        NativeMetadataInterceptor nativeInterceptor;
+        CallCredentialsSafeHandle credentials;
+
+        public NativeMetadataCredentialsPlugin(AsyncAuthInterceptor interceptor)
+        {
+            this.interceptor = GrpcPreconditions.CheckNotNull(interceptor, "interceptor");
+            this.nativeInterceptor = NativeMetadataInterceptorHandler;
+
+            // Make sure the callback doesn't get garbage collected until it is destroyed.
+            this.gcHandle = GCHandle.Alloc(this.nativeInterceptor, GCHandleType.Normal);
+            this.credentials = Native.grpcsharp_metadata_credentials_create_from_plugin(nativeInterceptor);
+        }
+
+        public CallCredentialsSafeHandle Credentials
+        {
+            get { return credentials; }
+        }
+
+        private void NativeMetadataInterceptorHandler(IntPtr statePtr, IntPtr serviceUrlPtr, IntPtr methodNamePtr, IntPtr callbackPtr, IntPtr userDataPtr, bool isDestroy)
+        {
+            if (isDestroy)
+            {
+                gcHandle.Free();
+                return;
+            }
+
+            try
+            {
+                var context = new AuthInterceptorContext(Marshal.PtrToStringAnsi(serviceUrlPtr),
+                                                         Marshal.PtrToStringAnsi(methodNamePtr));
+                StartGetMetadata(context, callbackPtr, userDataPtr);
+            }
+            catch (Exception e)
+            {
+                Native.grpcsharp_metadata_credentials_notify_from_plugin(callbackPtr, userDataPtr, MetadataArraySafeHandle.Create(Metadata.Empty), StatusCode.Unknown, GetMetadataExceptionMsg);
+                Logger.Error(e, GetMetadataExceptionMsg);
+            }
+        }
+
+        private async void StartGetMetadata(AuthInterceptorContext context, IntPtr callbackPtr, IntPtr userDataPtr)
+        {
+            try
+            {
+                var metadata = new Metadata();
+                await interceptor(context, metadata).ConfigureAwait(false);
+
+                using (var metadataArray = MetadataArraySafeHandle.Create(metadata))
+                {
+                    Native.grpcsharp_metadata_credentials_notify_from_plugin(callbackPtr, userDataPtr, metadataArray, StatusCode.OK, null);
+                }
+            }
+            catch (Exception e)
+            {
+                Native.grpcsharp_metadata_credentials_notify_from_plugin(callbackPtr, userDataPtr, MetadataArraySafeHandle.Create(Metadata.Empty), StatusCode.Unknown, GetMetadataExceptionMsg);
+                Logger.Error(e, GetMetadataExceptionMsg);
+            }
+        }
+    }
+}